Apple is famous for moving people along to the next software or OS upgrade. And iOS 6 appears to be no exception.
Less than 24 hours after it became available for public download, the new mobile OS was responsible for 15% of overall Apple device traffic on the Chitika ad network.
To measure this, Chitika said it "took a sample of millions of mobile ad impressions coming out of the Chitika Ad network ranging from September 19th to September 20th 2012. The growth rate of iOS 6 was then compared to total iOS Web usage using a time series to illustrate the rate of adoption of the new OS."
I asked Chitika whether they could extrapolate and tell me how many actual devices this represented. They declined to do that.
Source: Apple quarterly reports
If we make the assumption that the 15% of Chitika traffic translates 1:1 into individual devices -- in other words, 15% of the traffic is from 15% of all the iOS devices -- then we can crudely extrapolate using the chart above.
The iPhone 4 and 4S can upgrade to iOS 6. Apple hasn't broken out the sales figures by device generation but everything before Q2 2010 was iPhone 3GS and "below." The iPhone 4 was announced in June, 2010. Since Q2 2010 Apple has sold roughly 193 million iPhones.
It's safe then to say that well over 100 million iPhone 4 and 4Ss are in the market (that's a conservative estimate). If 15% of those now have iOS 6 running that means there are roughly 15 million such devices (around the world) that have downloaded the new OS only 24 hours after launch.
These numbers could be way off but they're probably not.
Today the pre-ordered iPhone 5s are arriving and people around the world are buying them from local stores. Accordingly the number of iOS 6 phones in market could be over 20 million (downloads + sales) within a week or two.